1. Field of the Invention
The present invention relates to a device and a method for optionally or selectively drawing in a cutout from a stack of several cutouts, or taking over a cutout from a separating cutting device, which separates the cutout from a material web. Cutouts in the sense of the present invention can be not only envelope cutouts, but also, for example, label cutouts or cutouts for lids to close off containers, particularly food containers.
2. The Prior Art
Two types of envelope production machines are known. In one type of machines, ready-cut envelope cutouts made available in stacks are drawn in by way of a so-called single-sheet intake. The drawn-in cutouts are then processed to produce envelopes. Such machines are usually referred to as sheet machines, where the term “sheet” indicates that individual cutout sheets are processed. In contrast to this type of machine, in the other type of machine, a material web, i.e. paper web rolled up onto a supply roll is processed to produce envelopes. Here, the material web is drawn into the machine directly from the supply roll, and cut to size at a suitable location of the processing path, by a separating cutting machine. In this way, the envelope cutouts are formed only within the envelope production machine. Such machines are referred to as roll machines.
So-called combination machines are also known, in which the operator of the machine can decide, as needed or on the basis of other circumstances, whether he/she wants to process cutouts that are present individually, by way of single-sheet intake, or a material web, i.e. paper web that has been wound up onto a supply roll. FIG. 3 shows that region of a combination machine known from the state of the art in which optionally or selectively, cutouts that are present individually or a material web can be drawn in.
If the combination machine is operated in the single-sheet intake operating mode, a single-sheet intake device 7 is used. In this connection, the bottommost cutout of a stack 2 that consists of several cutouts is pulled out from stack 2, by means of a first segment roller 8 that rotates clockwise and has suction air applied to it.
Segment rollers are known in the state of the art and have two different radii. These radii extend over a certain circumference region of the roller, in each instance, so that a step, which can be rounded off, occurs at two points of the circumference, in each instance. The segment roller usually rotates at a constant speed of rotation and works together with a counter-roller, which preferably consists of rubber and is passively driven by the segment roller. The envelope cutouts move through between the segment roller and the counter-roller, whereby only that circumference region of the segment roller that has the greater radius comes into contact with the cutout. The step of the segment roller that first comes into contact with the cutout to be accelerated is referred to as the grab edge. Since a segment roller accelerates the cutout in sudden manner after it has grabbed it, the segment roller is also referred to as a rip roller.
In FIG. 3, a segment roller 8 accelerates the cutout drawn in from stack 2 to the so-called cycle speed of the envelope production machine, and passes it, with precise register, to a transport roller 9 to which suction air is applied and which rotates counterclockwise. Transport roller 9 in turn passes the cutout on to a vacuum guide roller 10 that rotates clockwise. Vacuum guide roller 10 passes the cutout on further to a first work station 11 of the envelope production machine. Vacuum guide roller 10 is a cylindrical roller having suction air openings in the mantle surface, which are used to hold the cutouts on the roller circumference temporarily.
If the known envelope production machine is supposed to draw a material web 12 in from a supply roll, in contrast to single-sheet intake, the web guide or feed device 13 shown in FIG. 3 is used. Material web 12, which comes from a supply roll, not shown, is passed to a shape-cutting device 14 by way of a plurality of deflection rollers, which are not of particular interest here; the device essentially performs shaping cuts at the two edges of the material web. In FIG. 3, a one-piece material web 12 continues to be transported below a shape-cutting device 14. A separating-cut or cutting device 15 finally separates envelope cutouts from material web 12.
A second segment roller 16 that rotates clockwise and has suction air applied to it then grabs the separated cutout with its grab edge, and accelerates it to cycle speed. Finally, transfer of the accelerated cutout to vacuum guide roller 10 occurs, which passes it on further to a subsequent work station 11.
The known combination machine according to FIG. 3 has several disadvantages. For example, the production and maintenance costs in connection with the two segment rollers 8 and 16 are relatively high, and of course these high costs are undesirable. Furthermore, the so-called format change-over times, i.e. the time periods that are required to refit the machine from a first envelope format to a second envelope format are relatively long. These format change-over times are long because, in particular, two segment rollers 8 and 16 have to be replaced. Furthermore, the combination machine according to FIG. 3 requires not only the two segment rollers 8 and 16 but also additional transport rollers and deflection rollers, some of which have to have suction air applied to them cyclically. This arrangement results in both an increased generation of noise, and a greater need for space.